I wrote the following test and ran it under version 5.005_03 of perl. It showed that the warning was on the print line before the if. Printing undef will result in the warning.

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

use constant index1 => 0;
use constant index2 => 1;

my $rec = [ undef, 1 ];
print Dumper($rec);                       # inspect before if

print "$rec->[index1] $rec->[index2]\n";  # warnings here (line 11)

if ( defined $rec->[index1] &&
     $rec->[index1] ne '' &&
     defined $rec->[index1] &&
     $rec->[index1] eq '1' )
{
    print "OK\n";
} else {
    print "Not OK\n";
}

print Dumper($rec);     # and check again after if

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I don't think your if test will 'autovivify' anything because of the short circuit behaviour of the && operator. has anything to do with autovivification at all, given that the $rec has a fixed number of records. See pg's comments above and below. 

$VAR1 = [
          undef,
          1
        ];
Use of uninitialized value at ./p09.pl line 11.
 1
Not OK
$VAR1 = [
          undef,
          1
        ];

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In reply to Re: split, Use of uninitialized value by Roger
in thread split, Use of uninitialized value by Anonymous Monk

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